The semiconductor integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling down has also increased the complexity of processing and manufacturing ICs.
For multiple reasons including facilitating the scaling down process, three-dimensional devices such as fin-type field effect transistors (finFETs) have been developed for their high drive currents with small footprints compared to traditional planar device. Devices such as these have unique considerations associated therewith, and improvements are desired in this area.